In order that moisture be prevented from entering and damaging a telecommunication cable the cable ends are typically sealed temporarily prior to their being interconnected or terminated in the field. For years this has been done with cylindrical, heat shrinkable type end caps heat shrunk into sealing contact with the cable jacket about the cable ends. To remove this type of end cap an operator merely severed the cable at a location adjacent the end cap and discarded the cap and cable end segment located within.
Recently, telecommunication cables have been "preconnectorized" at the cable manufacturing plant in order to facilitate field connectorization. This entails attaching the end of each cable wire at the factory to a metallic connector, arranging the various connectors into one or more groups, and then bagging the groups into a bundle. Since the bundle of connectors occupies a space diametrically greater than that of the cable itself, the end portion of an end cap encasing the bundle has had to be made wider than that portion sealed to the cable jacket. As such reconfigured end caps can no longer be removed by merely severing the cable, since this would also cut off the bundle of connectors, new end cap removable methods have had to be devised.
One of the first end seals developed for pressurized. preconnectorized cables was a polyethylene bag with foam. The bag was taped to the cable while the foam layer inside the bag provided mechanical protection and was, at best, unreliable. Another early end seal for pressurized, preconnectorized cables was that known as the "Boot and Bag" which comprises a rubber boot placed about the connectors with a tapered boot neck taped tightly to the cable jacket. The boot is overlayed with a fabric cover which also is taped tightly to the cable jacket in order to support the rubber boot. This type of end seal has had to withstand pressure forces that tend to propel the bag off of the end of the cable. Although it is not believed that a boot and bag have ever been propelled from a cable end they nevertheless have possessed this potential and have also had a tendency to be leaky.
The next end seal developed for preconnectorized telecommunication cables was that termed the "One Piece" type end cap. This end cap, which is made of high density polyethylene plastic, is bottle-shaped and has its neck crosslinked and irradiated so as to be heat shrinkable. Once it is placed about the cable bundle heat is applied to its neck causing it to shrink down upon an adhesively coated section of the cable jacket adjacent the bundle. Unfortunately, the One Piece type end cap has proved to be quite costly, difficult and potentially dangerous to remove as by the use of embedded rip wires and heating torches.
Most recently a "Two Piece" end cap, also composed of high density plastic, has been developed for pressurized, preconnectorized telecommunication cables. This end cap, which also has an overall bottle-shaped appearance, has a cup-shaped, closed end section which is placed over the connector bundle and threadedly secured to an open ended, reducer section that is placed about the cable prior to formation of the cable bundle. The reducer section itself has a relatively narrow open neck end that closely overlays the cable jacket and is sealed thereto by means of heat shrinkable tubing shrunk down upon the open neck end and that portion of the cable jacket extending out from it. The reducer section also has a relatively wide shoulder end sized to be threaded into the cup-shaped, closed end section of the end cap. A thermo-compression seal is made over the threaded junction of the two sections.
As previously mentioned end caps of all types must be removed from the cable ends of connectorization. Again, with earlier cables that were not preconnectorized the cable was merely severed at a point next to the heat shrunk cap, the cable wire ends stripped of insulation and the connections made. With the Boot and Bag type end seal the fabric cover and rubber boot was tediously cut away as with a knife. With the One Piece end cap a rip wire was seated between the adhesive coated cable jacket and end cap neck. During its removal the rip wire would be coiled in cutting through the neck portion, in the familiar sardine can opening fashion, to a circumferential incision in the larger portion of the cap made with a saw. This latter procedure was particularly slow and tedious to perform in the field.
With the newer Two Piece type end cap the embedded rip wire approach cannot be practically used due to the absence of adhesive between the cap and cable jacket through which the wires would have to pass in a sealed, leak free fashion. Here it is necessary to remove not only the cup-shaped, open end section but also the reducer section since without its removal it would be very difficult to mount the cable end into a splice case or to route it to a pedestal type terminating block. In order that this type end cap may be removed, a circumferential cut has been made in the cap about that portion of the cable wires fanning out from the cable jacket towards the connector bundle. The cup-shaped, closed end section was then manually removed. Next a second, conical incision was made in the end cap closely adjacent the point at which the end cap curves inwardly to the narrow neck end placed closely about the cable jacket. Though at this point the end cap does not protrude very far away from the cable jacket it does necessitate the incurrence of risk that the cutting action may damage the cable itself. This danger is enhanced by the fact that such a cut is at an awkward angle for it to be made manually, being oriented generally parallel with the cable jacket and towards the cable bundle. Inherent with this also is the risk of damage being made to the connectors themselves in view of the difficulty of forming an incision in the oddly shaped reducer section.